Grain dryer



July 11, 1967 w. s. AUSHERMAN GRAIN DRYER 2 Sheets-Shed 1 Filed July 6, 1964 I36 011 BEEF/I Y I INVENTOR. WILLIAM S. AUSHERMAN ATTORNEY Jul 11,1967 w. s. AUSHERMAN GRAIN DRYER 2 Sheets-Sheet z 0 Filed July 6, 1964 INVENTOR. v WILLIAM S. AUSHERMAN Maw ATTQYRNEY United States Patent Filed July 6, 1964, Ser. No. 380,576 1 Claim. (Cl. 34-174) The present invention relates to new and useful improvements in grain dryers of the type having a vertical annular drying chamber disposed in spaced relation about a central vertical auger means whereby grain discharged from the lower end of the annular drying chamber is moved upwardly for either recirculation through the drying chamber or for storage, and in particular the present invention relates to an improved means for moving grain from the lower discharge end of the annular drying chamber to the inlet at the lower end of the auger means.

The primary object of the present invention is to provide means for urging radially inward movement of grain discharged in an annular pattern at the lower end of a vertically extending annular drying chamber towards the inlet at the lower end of a centrally positioned vertical auger in such a manner that the vertical height between the lower discharge end of the annular drying chamber and the inlet of the auger means can be minimized with resultant minimization of the overall height of the grain dryer for any given vertical height of the drying chamber.

Another very important object of the invention in accordance with the preceding object of the invention is to prevent or otherwise greatly lessen any tendency of the flow of grain to become clogged or uneven in any circumferential portion of the drying chamber adjacent the lower discharge end thereof.

Broadly stated, the invention has to do with the provision in combination with a grain dryer of the class wherein a vertical annular drying chamber is arranged to discharge material passing downwardly therethrough on a bottom wall and surrounds in spaced relation a vertical auger for raising material from a central portion of the bottom wall of means for urging radially inward movement of material discharged on the bottom wall from the drying chamber toward the central portion of the bottom wall, said means comprising a hub mounted for rotation about a vertical axis that is centrally disposed with respect to the annular drying chamber, and said hub being provided with radially extending rake means disposed in close proximity to the upper surface of the bottom wall and terminating radially adjacent the lower end of the drying chamber for urging radially inward movement of material on the bottom wall in response to rotation of the hub in one direction.

Another aspect of the invention relates to apparatus of the type defined in the preceding paragraph wherein the auger includes an auger tube with the hub being hollow and mounted for concentric rotation on the auger tube.

The rake means referred to in the preceding paragraphs can in a preferred embodiment of the invention comprise a plurality of radially extending arms spaced above the bottom wall, with each of such arms having disposed therebelow and fixed thereto an elongated radially extending element in close proximity to the bottom wall with the major dimension of the elongated element being inclined to its radius from the hub.

While it is not essential to the practice of the invention, the bottom wall specified in the preceding paragraphs is preferably substantially fiat and horizontal so as to occupy a minimum of vertical height, rather than being conventionally funnel or frusto-conical in shape.

An important feature of the preferred embodiment of the invention is that the bottom -wall is horizontal and suestantially flat with rotatable rake means disposed in close proximity to the upper surface of such bottom wall for urging movement of grain deposited in an annular pattern about the periphery of the bottom wall toward the center of the bottom wall and the inlet of the auger means.

Another important feature of the present invention is the mounting of the rake means on a hub or sleeve that is mounted for rotation on the auger tube.

Still another feature, though optional, of the invention related to the feature specified in the preceding paragraph is that the hub or sleeve of the rake means is vertically slidable upon the auger tube in such an arrangement that the lower end of the hub or sleeve is above the inlet opening of the auger sleeve and so that the weight of the rake means including the hub or sleeve bears yieldingly against the bottom wall of the dryer through the raking elements of such rake means.

Yet another feature of the invention resides in the provision of rake means that includes an arm fixed to the hub or sleeve, such arm being spaced above the bottom wall of the dryer and carrying therebelow a plurality of elongated raking elements that are each inclined in the same direction to the radius and having overlapping radial extents.

Other aims, purposes, objects, advantages, aspects and features of the invention will become evident during the forthcoming description of a preferred embodiment of the invention illustrated in the accompanying drawings, wherein:

FIGURE 1 is a central vertical sectional view of the grain dryer of this invention, with only a portion of the driving means provided for the auger, rake means and fan being shown;

FIGURE 2'is a top view of the dryer shown in FIG- URE 1;

FIGURE 3 is a horizontal sectional view taken upon the plane of the section line 33 shown in FIGURE 1;

FIGURE 4 is an exploded and enlarged detail view of the rake means; and,

FIGURE 5 is an enlarged horizontal sectional detail talken upon the plane of the section line 5-5 in FIG- Referring now to the drawings wherein like numerals designate like parts throughout the various views, the

or annular base 12 preferably formed of angle iron so as to be L-shaped in cross section, and spaced about the periphery of the annular base 12 and rigidly attached at their lower ends as by welding or the like to the base 12 is a plurality of upstanding angle iron supports or columns such as those designated at 14, 16 and 18. The upper ends of the support standards or columns such as those shown at 14, 16 and 18 are secured as by welding or the like to an annular ring of angle iron 20 similar to the base 12.

An annular ring 22 of angle iron is fixed to the support columns 14, 16 and 18 in spaced relation above the annular base 12, such ring 22, like the base 12 being horizontal, circular and disposed within the support columns 14, 16 and 18. A flat bottom wall 24, which can be circular in shape of heavy gauge galvanized sheet iron or steel, is mounted upon the support ring 22 and secured thereto by any suitable means such as by riveting or removable nuts and bolts, not shown, to have its outer periphery in engagement with the support columns such as those indicated at 14, 16 and 18.

A pair of concentric, radially spaced outer and inner metallic screens or perforate walls 26 and 28, respectively, are provided such as conventionally employed in grain dryers. It is preferred that the screens 26 and 28 be radially spaced apart some three to five inches and preferably screen 26.'

The vertical channel iron members 30, 32 and 34 inaddition to reinforcing the vertical supports 14, 16 and 18 3. about four inches. The outer cylindrical screen 26 is circular in horizontal configuration and is disposed within the vertical supports such as those designated at 14, 16 and 18 and is suitably secured to the radially inward sides of such vertical supports, the outer cylindrical screen 26 extending from the bottom wall 24 to the upper annular ring 20. The juncture between the lower edge of the cylindrical screen 26 and the outer periphery of the bottom wall 24 being sufiiciently tight as to prevent the passage of grain between the screen 26 and the bottom wall 24.

A plurality of vertical channel iron members equal in number to the vertical supports (such as those indicated at 14, 16 and 18) is provided, and such channel iron members are respectively associated with the vertical supf ports as clearly shown in FIGURES 2 and 3, wherein it tical supports designated at 14, 16 and 18 being designated at 30, 32 and 34. As shown in FIGURES 2 and 3, the radially outward flanges of the channel iron members 30, 32 and 34 are seated against the. inner surface of the outer screen 26 in direct opposition to the vertical angle iron supports 14, 16 and 18 and are secured thereto by means of bolts or rivets, not shown, extending through the additionally serve to space and support the cylindrical inner screen 28, the latter being disposed within and suitably secured to the radially inward flange portions of the vertical channel iron members such as those designated at 30, 32 and 34.

The vertical channel iron members 30, 32 and 34 have their lower ends spaced above the bottom wall 24 (some three to nine inches and preferably about six inches), as clearly shown in FIGURE 1, and have their upper ends at a position spaced substantially below the annular ring 20. The vertical extent of the cylindrical inner screen or perforate wall 28 corresponds to that of the vertical channel 7 iron members 30, 32 and 34in an arrangement such that an annular drying chamber 36 is defined between the outer and inner screen or perforate walls 26 and 28 having a vertical extent such that its lower end is disposed and spaced above the outer peripheral annular portion of the edge being positioned upon and suitably fixed to the radially inward flange'portions of the upper ends of the vertical channel iron members such as those indicated at 30, 32

and 34 in an arrangement in which the lower and outer,

peripheral edge of the top wall 38 makes a sufliciently tight juncture with the peripheral upper edge of the inner screen or wall 28 as to preclude the movement of grain therebetween. Vertically aligned openings 40 and 42 are provided centrally of the bottom wall 24 and the top Wall 38, respectively, and an anger tube 44 extends through the openings 42 and 44 and is fixedly secured thereto in any suitable manner to the bottom wall 24 and the top wall 38. It will be noted that the top wall 38 at its juncture with the auger tube 44 is preferably spaced substantially below the upper edge of the outer screen 26 while yet being spaced substantially above the upper edge of the inner screen 28. Also, as clearly shown in FIGURE 1,

' the auger tube 44 extends for a short distance below the bottom wall 24.

As thus far described, it will be evident that the space surrounded by that portion of the upper screen 26 extending above the inner screen 28 together with the top wall 38 constitutes an annular bin or upper grain storage comdrying chamber 36, it being noted that the slope. of the conical top wall 38 is sufiicient for grain toslide thereon into the drying chamber 36. It will furthermore be evident that grain entering the drying chamber 36 from the bin 46 will descend vertically by gravity down through the annular drying chamber 36 to be deposited upon the outer peripheral annular portion of the bottom wall 24.-

An annular air chamber 59 surrounding the auger tube 4 is defined within the space bounded by the bottom and top walls 24 and 38 and the inner screen 28 such that air,

preferably heated, introduced into the air chamber 50 will pass radially outwardly from such chamber 50 through the metallic screens or walls 28 and 26 and hence 7 through the annular drying chamber 36 defined between the screens or perforate walls 2 8 and 26 so as to subject grain in the annular drying chamber 36 to the drying effects of the passage of such air, preferably heated, there through. Means is provided for introducing air (which can, if desired, be. heated) into the air chamber which comprises a tubular conduit 56 tightly fitted through aligned openings in the inner and outer screens 28 and 26 and secured to the latter, whereby air from outside the dryer 10.can be introduced'into the air chamber 50, such conduit 56 being suitably supported upon the vertical supports by means not shown as will be understood by those conversant with extant commercially marketed grain dryers. The outer end of the conduit 56 is closed as indicated at 58, and a fan shaft 60 is journaled through the closed end wall 58 of the conduit 56 i V and a spider 62 fixed in the conduit 56. The end of the fan shaft 68 disposed within the conduit 56 is provided with a fan 64, and the end of the fan shaft; 60 projecting from the conduit 56 is provided with a pulley 66, where-.

by the'fan 64 can in any conventional manner be rotated by the action of a prime mover, not shown, drivingly connected to the pulley 66 by a belt partially shown at 68. A conventional flame or combustion flame heater such as can be fueled by liquified petroleum gases (butane, propane, etc.) is designated at 70, and such conventional heater 70 has communication with the conduit 56 through lateral openings 72 in the latter, whereby rotation of the fan'64 will draw outside air inwardly through the heater 70 whereby such indrawn air is heated (if the heater is ignited) and then cause such air to be forced into the air chamber from whence the air, heated, if desired, passes radially outward through the annular dry- 7 ing chamber 36 as previously described.

The upper and lower ends of the auger tube 44 are provided with closure walls 74. and 76, and an anger 78 is disposed within the auger tube 44 and has the opposite ends thereof journaled through the closure walls 74 and 76, the lower end of the auger shaft being provided with a pulley 80 by means of which a'prime mover, not shown,

can impart rotation to the auger 78 by the operation of a drive belt partially shown at 82.

Immediately above the position at which the auger tube 44 passes through the bottom wall 24, the auger tube 44 is provided with at least one inlet opening or port such as the one shown at 86, it being understood that a circumferentially spaced plurality of such ports can be provided, and the auger tube 44 is provided adjacent its upper end with a plurality of ci-rcumferentially spaced outlet openings or discharge ports 88. A cap or thimble is journaled on the top of the auger tube 44 having a plurality of discharge ports 92 arranged so as to be'registrable with the discharge openings 88 in a plurality of angularly adjusted positions of the thimble 90, such relative position of the thimble or cap '90 and consequent concurrent registration of all of the openings 88 and 92 being shown in FIGURE 5. The cap or thimble 90 is additionally provided with a downwardly inclined spout'94, the lower end of which projects radially outward beyond the V V outer screen 26. The thimble or cap 90 includes a passage-,

way 96 communicating with the interior of the spout 94 which is registrable with any selected one of the openings 88 upon appropriate angular adjustment of the cap or thirnble 90, it being noted that when the cap or thimble 90 is adjusted to register the opening 96 with one of the openings 88 that the cap or thimble 90 serves to close all the other openings 88. Thus, grain forced upwardly through the auger tube 44 can selectively be directed to be discharged through the spout 94 in a selected direction or be caused to pass directly downwardly into the bin 46, for recirculation through the annular drying chamber 36.

As pointed out hereinbefore, grain passing downwardly through the annular drying chamber 36 is deposited in an annular pattern about the outer circumferential peripheral portion of the bottom wall 24. According to the present invention, means is specially provided for positively urging grain so deposited upon the bottom wall 24 radially inwardly to a position immediately adjacent and surrounding that portion of the vertical extent of the auger tube 44 through which the inlet port or opening 86 extends. Such specially provided means are herein referred to as rake means and while the same can, as will become evident, take a variety of forms; the preferred construction of such rake means illustrated in the drawings will now be described. Such rake means are designated generally at 100, and comprises a hollow hub or sleeve 102 mounted for rotation on the auger tube 44. If desired or deemed expedient, any conventional means can be interposed between the hub 102 and the auger tube 44 for reducing friction and/or for limiting downward movement of the hub relative to the auger tube 44. Means of such character are commonplace and since such provision is not essential to practice of the invention the same is not illustrated or further described as no useful purpose would be served and could perhaps tend to obscure the invention. The sleeve 102 can if desired be vertically slidable on the anger tube 44 so that the weight of the rake means bears on the bottom wall 24 and the same is so illustrated in the drawings. It will of course be understood that this feature is not essential, and the rake means can be in close or even sliding engagement with the bottom Wall and yet supported if desired on the auger tube 44. The hub or sleeve 102 is as clearly shown in FIGURE 1 spaced above the bottom Wall 24, and the same is' preferably steel having a plurality of steel arms 104, 106, 108 and 110 welded thereto. As will be apparent upon inspection of FIGURE 3, the arms 104, 106, 108 and 110 extend directly outwardly from the hub or sleeve 102 along equiangularly spaced radii, and such arms have a length substantially less than the radius of the inner cylindrical screen or perforate wall 28. The arms 104, 106, 108 and 110 are attached to the hub or sleeve 102 adjacent the lower end of the latter and extend horizontally in spaced relation above the bottom wall 24. Each of the rake arms 104, 106, 108 and 110 are provided with elongated rake elements, and since such provision is the same for each of the rake arms, it will sufiice to describe in detail only such provision with respect to the rake arm 104. Directing attention especially to FIGURES 3 and 4, a pair of elongated rake elements are designated at 112 and 114. Though such elongated rake elements 112 and 114 can be of steel or other metals, they are preferably made of a straight grained hardwood such as oak. The elongated rake elements 112 and 114 are spaced below the rake arm 104 and are inclined in the same direction to the extent of the rake arm 104 so as to be inclined to the radius of the raking means 100. The elongated rake element 112 'is secured in spaced relation below the rake arm 104 by means of a bolt 116 extending upwardly through aligned openings 118 and 120 in the rake element 112 and the arm 104, respectively. The head 122 of the bolt 116 is preferably polygonal and is recessed in correspondingly shaped recess in the underside of the rake element 112 so as to be nonrotatable and not to constitute an obstruction along the undersurface, which may be planar, of the rake element 112. The upper threaded end of the bolt 116 is tightly secured by a nut 124 and a lock washer 126 seated against the top of the rake arm 104. A tubular spacer 128 is disposed about the bolt 116 between the rake arm 104 and the rake or raking element 112, such tubular spacer 128 preferably being hardened steel and having serrated upper and lower ends 130 and 132 that bite into and prevent relative rotation of the rake arm 104 and the rake element 112 when tightly clamped therebetween 0n tightening of the nut 124. The rake element 114, is like the rake element 112 preferably made of a straight grained hardwood and is nonrotably secured to the rake arm 104 in a similar fashion by means that includes a bolt 134, nut 136, lock washer 138 and a hardened tubular spacer 140 having serrated upper and lower ends 142 and 144. Such described attachment of the rake elements 112 and 114 to the rake arm 104 assures the rake elements 112 and 114 being retained in positions inclined to the radius of the rake means 100.

As may as been in FIGURE 3, the rake element 112 has its longitudinal dimension extending radially in a direction inclined to the radius of the rake means with one end of the rake element 112 being disposed adjacent the hub or sleeve 102 and its other radially outward end positioned radially outward of the bolt 134 and approximately midway between the axis of the hub or sleeve 102 and the outer cylindrical screen or perforate wall 26. Preferably, the bolt 116 or point of attachment of the rake element 112 is nearer the radially inward end of the rake element 112 than to the radially outward end. The elongated rake element 114 is generally parallel to and longer than the elongated rake element 112 and has its radially outward end positioned closely adjacent the outer cylindrical screen or perforate wall 26, and has its radially inward end positioned radially closer to the hub or sleeve 102 than is the radially outward end of the rake element 112. In other words, the radial extents of the rake elements 112 and 114 preferably differ in extent, overlap, and the joint radial extent of such rake elements 112 and 114 is such as the extend radially from closely adjacent to the auger tube 44 to closely adjacent the outer cylindrical screen or perforate wall 26. It will be manifest that clockwise rotation of the rake means 100 as viewed in FIGURE 3 will result in the radially outward end of the rake element 114 engaging grain deposited on the annular portion of the bottom wall 24 directly below the annular drying chamber 36 and will urge radially inward movement of such grain toward the auger tube 44 along a generally spiral path. Of course, grain so engaged and moved by the rake element 114 can be moved radially inward only to about a distance from the auger tube 44 corresponding to the radial spacing of the rake element 114 from the auger tube 44. Grain moved radially inward by the rake element 114 to such an extent is thereafter engaged by the rake element carried by the rake arm 106 that corresponds to the rake element 112, with such subsequent engagement serving to move the grain further radially inward into such close proximity to the auger tube 44 that it will be passed into the auger tube 44 through the inlet port or opening 86 for subsequent upward movement by the auger 78.

The lowermost edges or surfaces of the rake elements 112 and 114 as well as of all the rake elements associated with the other rake arms 106, 108 and are coplanar and rest upon the bottom wall 24 with a force equal to the weight of the rake means 110 by virtue of the hub or sleeve 102 being vertically slidable upon the auger tube 44. Should the rake means 100 be supoprted on the auger tube 44 as mentioned previously, the rake elements either slidably engage or are closely spaced to the bottom wall 24. The preferred arrangement wherein the rake means 100 rests upon the bottom wall 24 will allow the rake elements of the rake means 100 to rise up and ride over any minor obstructions that may be disposed on the top 7 7 of the bottom wall 24, it being noted that the vertical extent of the outer rake elements of the rake means 100 have a vertical extent at their outer ends that is less than the vertical spacing of the lower end of the screen 28 above the bottom wall 24 to permit a small degree of such vertical movement.

Means is provided for imparting rotation to the rake means 100, such means preferably taking the form of a sprocket wheel 160 fixed to the hub or sleeve 102 at a position spaced substantially above the lower end of the latter, together with a drive chain partially shown at 162 entrained over the sprocket wheel 160. The drive chain 162 extends outwardly from the dryer 10 through openings provided in the inner and outer screens 28 and 26 through Which tubular casings 170 and 172 extend, it being understood that the endless drive chain 162 extends through the tubular casings 170 and 172 to an external drive sprocket of a prime mover, not shown. The power train for driving the. rake means 100 can as is preferred incorporate any type of overload relief means. (not shown) such as a conventional safety ratchet to prevent structural breakage on the rake means encountering an unyielding obstruction.

From the foregoing, the operation of the dryer 10 will be readily understood by those skilled in the art. Grain to be dried is introduced into the bin 46 Wherefrom the grain passes downwardly into and fills the annular drying chamber 36. Until operation of the rake means 100 is initiated, such downward flow of grain from the bin 46 will only continued until the annular drying chamber 36 has been filled because the grain deposited on'the portion of the bottom wall 24 directly below the annular drying chamber 36 tends to block further flow. The gas or flame burner 70 is then ignited and the fan 64 actuated to initiate the forced introduction of heated air into the air chamber 50. Such forced introduction of heated air into the air chamber 50 results in air passing radially outward fromfthe air chamber 50 through the annular dry- I ing chamber 36. Some of such flow of heated. air from the chamber 50 occurs through the portion of the outer screen 26 below the screen 28 as well as some of the flow extending through the outer screen 26 above the inner screen 28; however, such relatively minor additional flows of heated air also serving respectively to dry' grain on the outer peripheral portion of the bottom wall 24 and in the lower'portion of the bin '46. Concurrent with initiating operation of the heater 70 and fan 64 or shortly thereafter, the auger 78 is actuated through the drive belt 82 for elevating grain introduced into the auger tube 44 through the inlet opening or port 86, and the rake means 100 is actuated for clockwise rotation as viewed in FIG- URE 3 by means of the endless drive chain 162 and sprocket 160. In the event one pass of the grain downwardly through the annular drying chamber 36 is adequate to achieve the degree of drying desired, the cap 90 and the spout 98 are arranged to deliver grain from the upper end of the auger tube 44 through thespout V 94 into a storage bin, an external conveyor, truck or the like not shown. On the other hand, if more than one pass of grain through the annular drying chamber 36 is necessary to achieve the degree of drying desired, the cap 90 7 it is to be particularly noted that the rake means 100 assures a smooth and continuous flow of grain radially in-' ward from directly beneath the annular drying chamber 36 to the inlet opening 86 of the auger tube 44, and it will also be noted that the passage of the outer end por- 's' 3 tion of the rake elements such as the rake element 114 beneath at least the inner part of the annular drying cham ber 36 around the entire circumferential extent of the latter serves to agitate and either break up or prevent .any clogging of grain in the annular drying chamber 36. It will be understood that any clogging or substantial obstruction to smooth downward flow of grain through the annular drying chamber 36 will tend to result in a channeling of flow downwardly through the drying chamber 36 with resultant possible excessive exposure of some grain to the heated air passing therethrough as well as possible under exposure of still other portions of the grain.

One of the chief advantages resulting from the provision of positive means for raking grain from beneath the annular drying chamber 36 to the inlet 86 of the auger 7 tube 44 is that a flat bottom wall 24 can be provided and reliance upon gravitational flow radially inwardly such as is unavoidably attended by an overall increase in the vertical height of the dryer may be entirely eliminated. The desirability of reducing dryer height for a given drying chamber height will be manifest when questions of movement of the apparatusare concerned such as greatly reducing problems in moving the dryer 10 beneath low bridges or moving the equipment into or out of buildings through doorways and the like,

Notwithstanding the particular suitability for and in a deed the necessity for the provision of rake means like or equivalent to the rake means disclosed and hereinbefore described for positively urging radially inward movement of grain from beneath the annular drying chamber to the auger tube 44 when the dryer has a fiat bottom wall such as the bottom wall 24, it is within the scope of the present invention to augment conventional grain dryers having annular drying chambers and funnel-like or frusto-conical bottoms with positive rake means inasmuch as such rake means can lessen the degree of slope of the frusto-conical bottom that would otherwise be necessary for gravity op eration while at the same time causing agitation in space adjacent the lower edge of the annular drying chamber 7 such as to make the How of grain down through the annular drying chamber substantially uniform about its entire circumferential extent. Accordingly, the Hat bottom wall 24 of the present invention may be considered the ;all vertical height, but for the further reason that the making of radial inward movement of grain entirely or at least largely dependent upon' the positive action of rake means is much more conducive to making the flow rate downwardly throughout the circumferential extent of the annular drying chamber 36 uniform, inasmuch as the rake means is substantially constant in its openation in all' directions. It is definitely preferred and indeed the advan- '1' tages of this invention will largely be lost if the bottom wall has a slope great enough for unaided gravitational flow as the latter can be very unequal about circumference retained in its normal position by conventional means, not. shown, it being understood that the cover is received in the opening and the upper surface of the cover 182 is substantially coplanar with the upper surface of the wall 24. As will be obvious the manhole on removal of the cover 182 permits accessibility to permit dislodg'mentof obstructions, lubrication of the hub or sleeve 102 as may I be necessary, etc.

The invention has been described in what may be deemed greater detail than necessary to convey a full and complete understanding of the principles involved to those normally skilled in the art; however, this has been done to be assured to such fact, and accordingly, any restriction in scope of the invention is not to be implied by the extent of the detail presented. With this in mind and considering the susceptibility of the invention to numerous variations without departing from the spirit or scope of the invention, the latter must be determined upon consideration of the appended claim.

I claim:

In a grain dryer of the class wherein a vertical annular drying chamber is arranged to discharge material passing downwardly therethrough on the upper surface of a peripheral portion of a bottom wall, such peripheral portion of the bottom wall being concentrically spaced about a central vertical auger for raising material from the upper surface of the bottom wall, said auger including an anger tube having a closed lower end, said auger tube having an inlet opening in a side thereof at a position adjacent the upper surface of the bottom wall, the combination therewith of means for urging horizontal radially inward movement of material upon the upper surface of the bottom wall throughout the radial extent of the latter from close radial proximity to the peripheral portion of the bottom wall to the inlet opening in the auger tube, said means comprising a hub mounted for rotation upon the auger tube, said hub being provided with radially extending rake means disposed in close proximity to the upper surface of the bottom wall and terminating radially adjacent the lower end of the drying chamber for urging horizontal and radially inward movement of material on the bottom wall in response to rotation of the hub in one direction, and said hub being vertically slidable on the auger tube and being positioned on the auger tube above the inlet opening, with said rake means depending from the hub.

References Cited UNITED STATES PATENTS 742,385 10/1903 Blaisdell 25923 1,856,361 5/1932 Thorne 222240 1,879,680 9/1932 Hartley et a1 34-179 X 2,925,666 2/1960 Gilmore et al 34102 3,078,590 2/1963 Batterton 34-174 3,199,434 8/1965 Piel 34174 MARTIN P. SCHWADRON, Primary Examiner.' FREDERICK L. MATTESON, JR., Examiner. B, L. ADAMS, Assistant Examiner. 

